Cooling system for a vehicle

ABSTRACT

A box-like cooling system ( 10 ) is provided for use in a vehicle. The system ( 10 ) include a plurality of heat exchangers ( 16, 18, 20 ) in a box-like arrangement around a radial fan ( 12 ) that directs a radial air flow through the cores ( 42 ) of the heat exchangers ( 16, 18, 20 ). The system ( 10 ) includes a front wall ( 22 ) having an inlet opening ( 60 ) for the air flow drawn by the fan ( 12 ), and a plurality of dynamic air flow ports ( 66 ) that are closed when the fan ( 12 ) is in an operating state providing the radial cooling air flow to the heat exchangers ( 16, 18, 20 ), and are open when the fan ( 12 ) is in a non-operating state and there is a dynamic air pressure on the front wall ( 22 ) produced by forward movement of the vehicle so as to allow a cooling air flow through the ports ( 66 ) into interior space ( 26 ) of the cooling system ( 10 ) and then through the cores ( 42 ) of the heat exchangers ( 16, 18, 20 ).

FIELD OF THE INVENTION

[0001] This invention relates to cooling systems and more particularly to cooling systems for vehicles wherein a plurality of heat exchangers form a box-like arrangement around a radial fan to receive a radial cooling flow therefrom and dynamic air pressure is produced on the cooling system by relative motion between the vehicle and the surrounding environment.

BACKGROUND OF THE INVENTION

[0002] Box-like cooling systems that arrange a plurality of heat exchangers around a radial fan to receive a radial cooling air flow therefrom are known for use in vehicles. Examples of such cooling systems are described in an German application DE 199 50 755 A1 and then EP 1 045 217 A1. In principal, because of their use of radial fans, the cooling systems of this type are, in principal, more efficient then conventional cooling systems where an individual heat exchangers are arranged in succession.

[0003] However, when used in vehicles, the question of efficiency should be viewed from the standpoint of total energy balance for the vehicle. In this regard, the fan which draws a cooling air flow through the core(s) of the heat exchanger(s) is typically driven electrically or directly by the engine and is typically only placed in operation as required. In this regard, in conventional cooling systems, the large cross section of the heat exchanger cores facing the front of the vehicle can permit a relatively high volume flow of cooling air as a result of the dynamic air pressure created by forward movement of the vehicle, which can be an adequate flow of cooling air when the cooling requirements for the heat exchangers are relatively low. However, in box-like cooling systems, the ability to provide an adequate volume of cooling air flow solely from the dynamic air pressure created by forward movement of the vehicle is complicated by the desire to use the radial fan to its best ability during its operating phases.

SUMMARY OF THE INVENTION

[0004] It is the principle object of the invention to provide an improved cooling system for a vehicle.

[0005] It is another object of the invention to provide an improved cooling system that utilizes a radial fan to supply a cooling air flow to the heat exchangers of the cooling system in one mode, and a dynamic air pressure generated by movement of the vehicle to provide a cooling air flow in another mode.

[0006] At least some of the above advantages are achieved in a cooling system provided for a vehicle and including a radial fan rotable about an axis, a plurality of heat exchangers spaced radially from the fan and arranged around the fan to receive a radial air flow therefrom, and a front wall. The fan has a non-operating state wherein the fan is not driven about the axis, and operating state wherein the fan is driven about the axis to deliver a radial air flow to the cooling system. The heat exchangers bound in interior space of the cooling system. The front wall covers an opening to the interior space bounded by the heat exchangers. The front wall includes an air inlet to direct an axial air flow to the fan, and a plurality of dynamic air flow ports spaced from the air inlet. The ports have an open state wherein the ports allow a cooling air flow into the interior space in response to the radial fan being in the non-operating state and a dynamic air pressure on an exterior side of the front wall, and a closed state wherein said cooling air flow into the interior space is substantially blocked in response to the fan being in the operating state.

[0007] In one aspect, the ports include a plurality of openings through the front wall and at least one flapper valve having a closed position wherein the valve covers at least one of the openings in response to the radial air flow of the fan, and an open position wherein the valve is spaced from the opening to allow the cooling air flow in response to the dynamic air pressure being greater than an air pressure in the interior space.

[0008] In one form, the at least one flapper valve includes a flexible member cantilevered to an interior surface of the front wall.

[0009] In one aspect, the ports include a plurality of openings through the front wall and at least one closure element movable between a closed position and an open position in response to signals that control the operating and non-operating states of the fan.

[0010] Other objects and advantages of the application will become apparent after reviewing the specification, including the appended claims and drawings.

DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a perspective view of a cooling system embodying the present invention;

[0012]FIG. 2 is an enlarged, partial section view taken from line 2-2 in FIG. 1; and

[0013]FIG. 3 is an enlarged , partial section view taken from line 3-3 in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0014] A cooling system 10 in embodying the present invention is shown in FIGS. 1-3. The cooling system 10 includes a radial fan 12 rotatable about an axis 14, three heat exchangers 16,18, and 20 spaced radially from the fan 12 and forming a box-like arrangement around the fan 12 to receive a radial air flow therefrom, and a front wall 22 covering an opening 24 to an interior space 26 bounded by the heat exchangers 16, 18, and 20. The heat exchangers 16 and 18 are provided in the form of a pair of radiators positioned on the left side and the right side of the cooling system 10, and the heat exchanger 20 is provided in the form of a charged cooler positioned on the top of the cooling system 10. In the illustrated embodiment, there is no heat exchanger provided on the bottom of the cooling system 10, accordingly, a wall 28 best seen in FIGS. 1 and 2 is provided to close the bottom of the system 10. Additionally, a back wall is provided to close the back of the system 10.

[0015] The fan 12 includes blades or scoops 30, a rear wall 32, and a cover disk or ring 34 (best seen in FIGS. 2 and 3). The fan is responsive to control signals (shown schematically at 36) that control the operational status of the fan 12 between a non-operating state wherein the fan 12 is not driven about the axis 14, and an operating state wherein the fan 12 is driven about the axis 14 to deliver the radial air flow to the cooling system 10.

[0016] Each of the heat exchangers 16, 18, and 20 include a core 42 defined by flattened tubes 44 that extends between a pair of manifolds or collecting boxes 45, with fins 46 extending between the flattened tubes 44. Such constructions are known. The core 42 of the charge cooler 20 is larger in its core depth 48 than the core depth 30 of the heat exchangers 16 and 18 and includes two rows of the flattened tubes 44. Additionally, the width 50 of the charge cooler 20 is greater than the width 50 of the heat exchangers 16 and 18, which results in a distinct protrusion 52 of the charge cooler 20 extending forward beyond the front wall 22, as best seen in FIG. 2. A cover sheet 54 is provided to maintain the air flow within the interior space 26 of the cooling system 10 prior to directing the cooling air flow over the protrusion 52 .

[0017] The front wall 22 includes an intake or inlet opening 60 defined by a nozzle 62 that is centered on the axis 14 to direct an axial air flow to the fan 12 as it is drawn into the cooling system 10 by the fan 12. In this regard, for purposes of illustration, the fan axis 14 and the inlet 60 are located closer to the top of the cooling system 10.

[0018] The front wall 22 is exposed to an air flow that impinges against the front wall 22 as a result of the forward motion of the vehicle in which the cooling system 10 is mounted. This air flow produces a dynamic air pressure on an exterior side 64 of the front wall 22. To take advantage of this air flow, a plurality of dynamic air flow ports 66 are provided in the front wall 22 spaced from the air inlet 60, with the ports 66 having an open state wherein the ports 66 allow a cooling flow into the interior space 26 in response to the radial fan 12 being in the non-operating state and to the dynamic air pressure on the exterior side 64 of the front wall 22, and a closed state wherein the cooling air flow into the interior space 26 is substantially blocked in response to the fan 12 being in the operating state. To this end, in the illustrated embodiment, the ports 66 include a plurality of openings 68 through the front wall 22 and a plurality closure elements 70 in the form of flapper valves 72. More specifically, in the illustrated embodiment, a total of nine of the openings 68 are provided in the front wall 22, with two of the openings 68 located at the top of the front wall 22 spaced on either side of the front wall 22, and the remaining seven openings 98 being arranged beneath the intake opening 60. However, it should be appreciated, that the shape, number, and arrangement of the openings 68 can be varied depending upon the particular requirements of the cooling system 10. Further, in some embodiments it may be desirable for openings 68 and the front wall 24 to be a grate-like construction, i.e., designed in the fashion of a cooling grate or core. In FIG. 1 and FIG. 2, the upper two ports 66 are shown in the open state, i.e. with the flapper valve 72 positioned away from the opening 68 to allow the cooling air flow into the interior space 26. For purposes of illustration, the lower ports 66 are shown in the closed state in FIGS. 1 and 3 with the flapper valves 72 covering their respective openings 68 to substantially block the cooling air flow from flowing through the openings 68 into the interior space 26. While the upper port 66 are shown in the open position and the lower port 66 are shown in the closed position or state, it should be understood that this is done only for purposes of illustration and that in actual operation of the system 10, all of the ports 66 are ideally in the same state or position, i.e. all of the ports 66 are either open or closed, depending upon the desired operating state for the ports 66.

[0019] The flapper valves 72 are preferably made of a flexible sheet of material that is fastened to an interior surface 74 of the front wall 22 in a cantilever fashion, as best seen in FIG. 2. For example, flapper valve 72 could be formed from a tab of a suitable rubber material having an edge fastened to the interior surface 74.

[0020] It should be appreciated that in the preferred embodiment, the air pressure within the interior space 26 generated by the radial air flow when the fan 12 is in the operating state operates to move the flapper valves 72 to their closed position covering the openings 68, but when the fan 12 is in a non-operating state, the dynamic air pressure on the front wall 22 produced by forward movement of the vehicle is sufficient to move the flapper valves 72 to their open position away from the opening 68 to allow the cooling air flow into the interior space 26 where it is then directed through the cores 42 so that heat can be rejected from the cores 42 to the cooling air flow.

[0021] Further, just as the shape, number and arrangement of the openings 68 can be configured differently, the flapper valves 72 can also be configured differently. For example, in some embodiments it may be desirable for several, smaller openings 68 to be closed by a single flapper valve 72. By way of further example, while the flapper valve 72 shown in FIG. 2 is fastened to the interior surface 74 at the top of the valve 72, it could be fastened to the inside surface 74 to the one side or the other of the openings 68. In this regard, depending on the positioning of the openings 68 relative to the fan 12, care must be taken so that the size of the flapper valve 72 does not allow the flapper valve 72 to interfere with or contact the fan 12 when the flapper valve 72 is in the open position. Preferably, the size of the flapper valve 72 should be sized to cover the openings 68 so that the openings 68 can be closed with a suitable tightness.

[0022] While the illustrated embodiments show the closure elements 70 in the form of the flapper valves 72, it should be understood that in some embodiments it may be preferred to provide other types of closure elements. For example, in some embodiments it may be desired to provide closure elements 70 that are movable between the closed position and the open position in response to the signals 36 that control the operating and non-operating states of the fan 12 by means of a suitable mechanism. For example, the closure elements 70 could be slidable louvers that are moved between the closed and open state by a pinion and rack, similar to the mechanisms disclosed in DE 197 24 728 A1. By way of further example, closure elements 70 made of a flexible material or of a material that is flexible in a windable or unwindable region, could be provided for movement via driven rollers or the like such as those disclosed in German unexamined patent application DE 0S 25 01 013 which drive a tape filter. In this regard, the closure element 70 could include a cover made of a rigid plate that is movable by means of a roller drive provided with upper and lower guides arranged on the front wall 22. By way of further example, the closure elements 70 could be provided in the form of shutters or diaphragms similar to the shutters or diaphragms utilized in a camera lens.

[0023] It should be understood follows. that while the flapper valves 72 are shown installed against the inside surface 74 of the front wall 22, it may be advantageous to some applications to install the closure elements 70 on the exterior side of the front wall 22.

[0024] The shape, number and arrangement of the ports 66 and the front wall 22 will be guided according to the volume of cooling air flow required for a given operating condition, how the cooling air flow must be distributed within the interior space 26 to the heat exchangers 16, 18, and 20, what types of closure elements 70 are selected, and the strength and stability requirements for the front wall 22, such as for example if the front wall 22 serves as a support element of the cooling system 10.

[0025] It would be appreciated that providing the cooling air flow port 66 the system 10 provides a box-like cooling system that can take advantage of the dynamic air pressure provided by forward movement of the vehicle, without having a significant and adverse effect on the efficiency on the radial fan 12 during its operating phases by allowing a cooling air flow into the interior space 26 when the fan is not operating and preventing the radial air flow of the fan from escaping through the front wall 22 during the operating state of the fan 12. This in turn can allow the cooling system 12 to operate over a larger operating range in dynamic pressure operation, i.e., without using the radial fan 12 so that less power is required. Thus, the engagement frequency and engagement time of the radial fan 12 can be reduced by the invention, which leads to reduced fuel consumption for the vehicle. 

I claim:
 1. A cooling system for a vehicle the provides an air stream with a dynamic air pressure to the cooling system produced by forward motion of the vehicle, the cooling system comprising: a radial fan rotatable about an axis, the fan having a non-operating state wherein the fan is not driven about the axis and an operating state wherein said fan is driven about the axis to deliver a radial air flow to the cooling system; a plurality of heat exchangers spaced radially from the fan and arranged around the fan to receive the radial air flow therefrom, the heat exchangers bounding an interior space of the cooling system; and a front wall covering an opening to the interior space bounded by the heat exchangers, the front wall including an air inlet to direct an axial air flow to the fan, and a plurality of dynamic air flow ports spaced from the air inlet, the ports having an open state wherein the ports allow a cooling air flow into the interior space in response to the radial fan being in the non-operating state and a dynamic air pressure on an exterior side of the front wall, and a closed state wherein said cooling air flow into the interior space is substantially blocked in response to the fan being in the operating state.
 2. The cooling system of claim 1 wherein said ports comprise a plurality of openings through the front wall and at least one flapper valve having a closed position wherein said valve covers at least one of said openings in response to the radial air flow of the fan and an open position wherein said valve is spaced from said opening to allow said cooling air flow in response to said dynamic air pressure being greater than an air pressure in the interior space.
 3. The cooling system of claim 2 wherein said at least one flapper valve comprises a flexible member cantilevered to an interior surface of said front wall.
 4. The cooling system of claim 1 wherein said ports comprise a plurality of openings through the front wall and at least one closure element movable between a closed position and an open position in response to signals that control said operating and non-operating states of the fan.
 5. The cooling system of claim 4 wherein said at least one closure element is located on the exterior side of the front wall.
 6. The cooling system of claim 4 wherein said at least one closure element is located on an interior side of the front wall. 